Google is testing a new form of ads where the ads animate and reform themselves as you place your mouse cursor over them. It is a form of animation within the Google AdSense ad formats.
@IncrediBILL posted videos of what these look like at WebmasterWorld when you interact with them. I reposted them on YouTube, instead of the Windows Media Video format, so you can all see them right here.
They look pretty wild, check them out:
Here is a skyscraper version:
Are you surprised Google is testing this with Google AdSense? Do you like them? Will they increase click throughs? Will they slow down web page load time?
I have not been able to replicate these myself.